Bis(2-chloroethyl) formal and mixtures thereof with phenols as solvents for polyester compositions and method of preparing same



3,042,545 Patented July 3, 1962 BIS(2-CHLOROETHYL) FORMAL AND MIXTURES THEREOF WITH PHENOLS AS SOLVENTS FOR POLYESTER COMPOSITIONS AND METHOD OF PREPARING SAME Arthur B. Beindorfi, Decatur, Ala, and Hobson D. De

Witt, New Wilmington, Pa, assignors, by mesne assignments, to Monsanto Chemical Company, a corporation of Delaware No Drawing. Filed July 23, 1959, Ser. No. 828,934 20 Claims. (Cl. 260-332) This invention relates to new compositions of matter and more particularly to new and useful compositions of matter comprising solutions or dopes of synthetic linear condensation polymters. it is further concerned with new compositions of matter which are capable of being formed into useful articles such as ribbons, films, bristles, fibers, filaments and the like.

This application is a continuation-in-part of our copending application, Serial No. 553,733, filed December 19, 1955, and entitled Bis(2-Chloroethyl) Formal as a Solvent for Polyester Compounds, now abandoned.

For the sake of simplicity, the present invention will be described as it is applied in the manufacture of fibers and filaments. However, the invention is not to be limited thereby except insofar as it may be limited by the appended claims.

Various methods are known for converting the polyesters described above into filaments and fibers, such as the so-called melt-spinning, wet-spinning and dry-spinning methods.

Melt-spinning comprises melting chips of a polyester on a heated grid and passing the melt through a filter bed of small particles, such as sand, and the like. Subsequently, the melt is forced through a spinneret and the filaments so formed are cooled. However, melt-spinning has certain disadvantages such as the employment of high temperatures which makes the addition of plasticizers and modifying agents difiicult, because there is a tendency for the added agents to discolor and decompose.

In the dry-spinning method the polyester is dissolved in a solvent therefor and extruded through a spinneret in the usual manner. The solution is extruded into an atmosphere of inert gas which may be heated. The motion of the inert gaseous atmosphere, the extruded fiber and the application of heat all aid in disposing of the volatile solvent.

The wet-spinning method in which a solution of polyester is extruded into a bath containing a non-solvent for the polyester has a number of advantages over the meltspinning method. For example, the wet-spinning method,

is generally more economical and can be carried out at lower temperatures. Therefore, plasticizers and other agents may be added with a minimum tendency toward discoloration and decomposition. Furthermore, certain types of plasticizers and modifying agents tend to be less compatible for blending in a melt at high temperatures, whereas they can be readily incorporated in a polyester solution at a low temperature. Solutions oiler the further advantage in that they may be easily cast into films or coatings of uniform thickness. This is extremely difficult with a molten composition because of its relatively high viscosity.

The wet-spinning method, however, has not been employed commercially because of the lack of suitable solvents. Generally polyesters are insoluble in the more common organic solvents. From the standpoint of low cost, solvent power, non-corrosiveness and ease of recovery, there is a scarcity of suitablesolvents for the more usual types of polyesters.

Accordingly, the principal object of the instant invention is the preparation of polyester solutions or dopes which are capable of being transformed into shaped articles.

Another object is to provide synthetic linear condensation polyester compositions in solutions which are stable and have non-gelation characteristics.

Another object of the invention is to prepare spinnable solutions of polyester compositions.

Other objects and advantages of the invention will be apparent from the following description.

The foregoing objects are accomplished by dissolving the synthetic linear condensation polyesters in his (2-chloroethyl) formal and like compounds or dissolving the synthetic linear condensation polyesters in mixtures of these compounds and phenols, such as phenol, chlorophenols, metacresol, resorcinol, and the like.

When preparing a solution of polyesters in a solvent mixture, the his (2-chloroethyl) formal may be employed in a range of 97% to 50% based on the total weight of the solvent, and the phenols in the range of 3% to 50%.

Solutions of high solids content and good stability can be prepared by mixing the polyester in the compounds mentioned hereinabove and heating to a temperature in a range of C. to the boiling point of the mixture. If desired, the mixture may be stirred while heating. However, stirring is not necessary to effect solution, although it has been found that the polyester goes into solution more smoothly and evenly and with a greater rate of speed when stirring is employed. Whether stirring is employed or not, a miscible mixture of the synthetic linear condensation polyester is attained. The maximum solids concentration of the polyester that can be obtained in the solution and the viscosity of the solution depend upon the nature of the polyester, the solvent mixture and the temperature. In the manufacture of filaments and fibers a polyester having a molecular weight of at least 10,000 is employed in making a solution. Lower molecular weight polyesters may be utilized when the solution to be formed is to be used as a coating or as a lacquer. In preparing solutions or dopes suitable for spinning into filaments and fibers, l0 to 25 percent by weight of the polyester, basedon the total weight of the solution, is suitable. While it is preferred to employ 10 to 25 percent by weight, based on the total weight of the solution, of the polyester in the solvent when the solution is to be used for the preparation of fibers and filament-s, it is to be understood that as little as 5 percent or less and as much as 30 percent or more of the polyester may be utilized when the solution is to be employed for other purposes, such as a coating or lacquer and the like, or when lower or higher molecular weight polyesters are to be dissolved in the new solvents of this invention. The amount of any specific polyester, which can be dissolved in the solvents of this invention, will be readily evident to those skilled inthe art.

The synthetic linear condensation polyesters contemplated in the practice of the invention are those formed from dicarboxylic acids and glycols, and copolyesters or modifications of these polyesters and copolyesters. In a highly polymerized condition, these polyesters and copolyesters can be formed into filaments and the like and subsequently oriented permanently by cold drawing. The polyesters and copolyesters specifically useful in the instant invention are those resulting from heating one or more of the glycols of the series HO'(CH -OH, in which n is an integer from 2 to 10, with one or more dicarboxylic acids or esterforming derivatives thereof. Among the dicarboxylic acids and ester-forming derivatives thereof useful in the present invention there may be named terephthalic, isophthalic acid, sebacic acid, adipic acid, p-carboxyphenoacetic acid, succinic acid, p,p-dicarboxybiphenyl, p,-p'-dicarboxycarbanilide, p,p'-dicarboxythiocarbanilide, p,p-di- 'erties, suchas the monofunctional ester-forming bon atoms.

carboxydiphenylsulfone, p-carboxyphenoxyacetic acid, pcarb'oxyphenoxypropionic acid, p-carboxyphenoxybutric acid, p-carboxyphenoxyyaleric acid, p-carboxyphenoxyhexanoic acid, pcarboxyphenoxyheptanoic acid, p,p-dicarboxydiphenylmethane, p,p dicarboxydiphenylethane,

500 to 5000, withthose agents having a molecular weight in the'range of 1000 to 3500 being preferred;

diphenylhexane, p,p-dicarboxydiphenylheptane, p,p'-dicarboxydiphenyloctane, p,p' dicarboxydiphenoxyethane,

.p,pf di'carboxydiphenoxypropane, p,p dicarboxydiphe nox'ybutane, p,p'.-dicarboxydiphenoxypentane, p,p-dicar-' .boxydiphenoxyhexane, 3-alkyl 4-(beta-carboxy ethoxy) benzoic acid, oxalic acid, glutaric acid, 'pimelic acid, suberic acid, aze-laic acid and the dioxy acids of ethylene dioxide having the general formula,

wherein n is an integer from 1 to 4, and the aliphatic and cycloaliphatic aryl esters and half esters, ammonium and amine salts, and the acid halides of the above named. compounds and the like.

Examples of the glycols which may be employed in practicing the instant invention are ethylene glycol, trimethylene glycol, tetramethylene glycol and decamethylene glycol, etc. Polyethylene terephtha-' late, however, is preferred because of the ready availability of terephthalic acid and ethylene glycol, from which it is made. It also has a relatively high melting point of about 250 through 255 C. and this property is particularly'dedustry,

' 'Among the modified polyesters and copolyesters which are useful in the parctice of the instant invention are the polyesters and ,copolyesters mentioned above modified with chainterminating groups having hydrophilic propp yethers bearing the general formula, (I) R, o t H2)m01.; 2)n' wherein R is an alkyl group containing 1 to 18 carbon atoms or an aryl. group containing 6 to 10 carbon atoms,

and m and n are integers from 2 to 22, and'x is a whole number indicative of the degree of polymerization, that is, x is an integer from 1: to 100 or'greater. Examples of such compounds are methoxypolyethylene glycol, ethoxypolyethylene glycol, n-propoxypolyethylene glycol, isopropoxypolyethylene glycol, butoxypolyethylene glycol, phenoxypolyethylene glycol, methoxypolypropylene glycol, methoxypolybutylene glycol, phenoxypolypropylene glycol, phenoxypolybutylene' glycol, methoxypolyrnethylene glycol, and the like. Suitable polyalkylvinyl ethers having one terminal hydroxyl group are the addition polymers prepared by the homopolymerization of alkylvinyl ethers wherein the alkyl group contains from 1 to 4 car Examples of such chain-terminating agents sirable in, the manufacture of filaments in the textile in- Materials suitable as chain-branching agents or crosslinking agents, which are employed to increase the viscosity or molecular weight of .the polyesters, are the polyols which havea functionality greater than two, that is,

atoms, for example, trimethylol ethane, tn'methylol propane, and like compounds up to trimethylol hexane; and

V the compounds having thejformula:

(CHhOH L wherein n is an integer from Ito 6. As examples of compounds having the above formula there may be named trimethylol benzene-1,3,5, triethylol benzene-1,3,5, tripropylol benzene-1,3,5, tributylol benzene-1,3,5, etc.

Aromatic polyfunctionalacid esters may also be employed in this invention as chain'branching-agents and' particularly those having the formula:

( Ft 1 7. GEO-Gilt n.

wherein n is an integer from'3, to 4 and R is an alkyl group containing 1 to 3 carbon atoms. As examples of compounds having the above formula there may be named trimethyl trimesate, 'tetramethyl pyromellitate,tetramethyl rnellophonate, trimethyl hemimellitate, trimethyl trimellitate, tetramethyl prehnitate, and the like. In addition, there may be employed mixtures of the" above esters which are obtained in practical synthesis. That is, in most instances when preparing any of the compounds having the above formula, other related compounds having the same formula may be present in small amounts as impurities. This does not afiect the compound as a chain-branching agent in the preparation of the modifiedpolyesters and copolyesters described herein;

are hydroxy polymethylvinyl, ether, hydroxypolyethylvinyl ether, hydroxy polypropylvinyl-ether, hydroxy polybutylvinyl ether, hydroxy polyisobutylvinyl ether, and the like. The chain-terminating agents or compounds may be employed in the preparation ofthe modified polyesters in amounts ranging from 0.05 mol percent to 4.0 mol per- 5 cent, based on the amount of dicarboxylic acid or dialkyl ester thereof employed in the reaction'mixture. It is to be noted that'when chain-terminating agents are employed alone, i.e., without a chain-branching agent, the maximum amount that can-be employed in the reaction mixture is 1.0 mol percent. Thus, unexpectedly, the addition of controlled amounts of chain-branching agents along 7 with the chain-terminating agents allows the introduction of an increased amount of the latter into the polymer terminating agents alone.

One will readily appreciate that the weight percent of chain-terminating agent which may be employed in this invention will vary with the molecular weight of the agent; The range of average molecular weight of the chain-ter rninating agents suitable for use in this invention is from chain than is otherwise possible when employing the chain- The chainebranching agents or cross-linking agents may be employed inthe preparation of the polyesters and copolyesters in amounts ranging from 0.05 mol percent to 2.4mol percent, based on the amount of dicarboxylic acid or dialkyl ester thereof employed in the reaction mixture.

7 The preferred range of chain-branching agent for use in thepresent invention is from 0.1 to 1.0 mol percent.

In the practice of the present invention, the calculated amounts of chain-terminating agent or chain-terminating agent and chain-branching agent or cross-linking agent are charged to the reaction vessel at the beginning of the first stage of the esterification reaction andthe reaction proceeds as in any well-known esterification polymerization.

' The first step or stage of the'reaction is carried out at atmospheric pressure and at a temperature in the range of C. to 250 C. and preferably-between and 220 C.;when from0.001'to 1.0percent by weight, based on the weight of the dicarboxylic acid or ester thereof, of asuitable esterification catalyst, such as manganous formate or zinc acetylacetonate, is employed. If desired,

the reaction may be carried out at pressures above or below atmospheric. Methanol is evolved which is continuously removed by distillation. At the completion of the first stage, the excess glycol, if any, is distilled oil prior I to entering the second stage of the reaction.

In the second or polymerization stage, the reaction is conducted at reduced pressures and preferably in the presence of an inert gas, such as nitrogen, in order to prevent oxidation. This can be accomplished by maintaining a nitrogen blanket over the reactants, said nitrogen containing less than 0.003 percent oxygen. For optimum results a pressure within the range of less than 1 mm. up to 5 mm. of mercury is employed. This reduced pressure is necessary to remove the free ethylene glycol that is formed during this stage of the reaction, the ethylene glycol being volatilized under these conditions and removed from the system. The polymerization step is conducted at -a temperature in the range of 220 to 300 C. The stage of the reaction may be etIected either in the liquid, melt or solid phase. In the liquid phase, particularly, reduced pressures must be employed in order to remove the free ethylene glycol which emerges from the polymer as a result of the condensation reaction.

In the preparation of the described polyesters, the first stage of the reaction takes place in approximately to 2 hours, when employing a suitable esterification catalyst. In the absence of a catalyst, times up to 6 hours may be necessary in order to complete this phase of the reaction. In the second stage, a reaction time of approximately 1 to 4 hours may be employed with a time of 1 to 3 hours being the optimum, depending on catalyst concentration, temperature, viscosity desired, amount of color allowable in the finished polymer, etc.

The'modified linear condensation polyesters, produced in accordance with the present invention, have a specific viscosity in the range of 0.30 to 0.60, which represents the 'fiberand filament-forming polymers. It is to be understood, of course, that non-fiber-forming polyesters may be produced by means of the present invention, which have a specific viscosity greater or less than that reiterated above and such polyesters are useful, for example, in the manufacture of coating compositions, lacquers, molding compositions, and the like. This specific viscosity range and variations thereof also are applicable to the unmodified polyesters, such as polyethylene terephthalate. The specific viscosity range of the fiber-forming polymers, that is, from 0.3 to about 0.6, indicates high molecular weight polymers of from about 10,000 to about 50,000 molecular weight.

If it is desired to produce shaped articles from the polyester solutions of the present invention which have a modified appearance or modified properties, various agents to accomplish these efiects may be added to the polyester solutions of this invention prior to the fabrication of the articles without any ill effects thereon. Such added agents might be plasticizers, pigments, dyes, antistatic agents, fire-retarding agents, etc.

The following examples are intended to illustrate the new compositions of the invention more fully, but are not intended to limit the scope of the invention, for it is possible to effect many modifications therein. In the examples, all parts and percents are by weight unless otherwise indicated.

Example I 9 grams of his (2-ch1oroethyl) formal and 1 gram of polyethylene terephthalate were mixed together and warmed with stirring to 185 C. where the polymer readily dissolved, yielding a clear fluid solution suitable for both wet or dry spinning.

Example II There was charged to a reaction vessel 82 grams of dimethyl terephthalate, 106.2 grams of ethylene glycol (approximately 88 ml.) and 8.2 grams of ethoxypolyethylene glycol having an average molecular weight of about 3050 (0.5 mol percent based on the mols of dimethyl terephthalate). Subsequently, 40 mg. of manganous formate was added to the reaction vessel. The reactants were well mixed and heated at 177 C. until solution was etfected. The mixture was maintained at this temperature for minutes to bring about the ester-interchange reaction. Thereafter, the temperature was raised to 225 C. to remove excess ethylene glycol and maintained at that temperature under a vacuum of less than 1 mm. of mercury for three hours to efiiect polymerization. There was obtained a high molecular weight polyester having a melting point of about 255 C. and a specific viscosity of about 0.3 at- 25 C. calculated in a 2 to 1 mixture of phenol-trichlorophenol containing 0.5 percent by weight of polymer. 9 grams of his (2-chloroethyl) formal and 1 gram of the polyester prepared in accordance with the above procedure were mixed together and warmed with stirring to 185 C. where the polymer readily dissolved yielding a clear fiuid solution suitable for both Wet and dry spinning.

Example III A polyester was prepared as in Example II but with approximately 16.4 grams of ethoxypolyethylene glycol (that is, about 1 mol percent based on the mols of dimethyl terephthalate). 9 grams of his (2-chloroethyl) formal and 1 gram of the polyester so prepared were mixed together and warmed with stirring to 185 C. where the polymer readily dissolved yielding a clear fluid solu tion suitable for both wet spinning or dry spinning.

Example IV 9 grams of his (2-chloroethyl) formal and, 2 grams of polyethylene terephthalate were mixed together and warmed with stirring to C. where solution began to occur. The temperature was raised to C. where the rate of solution was much faster. A clear, viscous solution was obtained after a few minutes which was suitable for wet or dry spinning.

Example V 7 grams of his (2-chloroethyl) formal, 1 gram of phenol and 2 grams of polyethylene terephthalate were mixed together and warmed with stirring at 170 C. where solution began to occur. The temperature was raised to 180 C. where the rate of solution was much faster, being facilitated by the added phenol. A clear, viscous solution was obtained after a few minutes which was suitable for wet or dry spinning.

Example VI 7 grams of bis (2-chloroethyl) formal and 1 gram of phenol were mixed with 2 grams of the polyester prepared in accordance with the procedure of Example III and heated with stirring to 170 C. where the polymer readily dissolved, yielding a clear fluid solution suitablefor both wet and dry spinning.

Example VII There was charged to a reaction vessel 1650 grams of dimethyl terephthalate, 1980 grams (approximately 1775 ml.) of ethylene glycol and 165 grams of methoxypolyethylene glycol having an average molecular weight of about 2000 (1.0 mol percent based on the mols of dimethyl terephthalate). There was also added to the reaction vessel 1.32 grams of pentaerythritol. Subsequently, 1.07 grams of zinc acetylacetonate were added to the reaction vessel. The reactants were well mixed and heated for about 90 minutes at atmospheric pressure and at a'temperature gradually raised from 155C. to 198C. until solution was effected. During this time methyl alcohol which was formed in the reaction was removed by distillation. Subsequently, the reactants were heated for about 45 minutes under atmospheric pressure at a temperature which was gradually raised from 198 C. to 240 C. to remove excess ethylene glycol. Then the temperature was raised from 240 C. to about 280 C. over a period of about 5 minutes while the pressure was gradually decreased from atmospheric pressure to about 1 mm. of

mercury; The reaction mixture was subjected for "about 1 /2 hours to'280" C. and about 1 mm. of mercury to effect polymerization. There was obtained a'high molecular weigh t' polyester having 'a melting point of about 255 C. andQa specific viscosity of 0.50 at 25 C.. calcu- .lated in a Zto' 1 mixture of phenol-trichlorophenol containing 0.5 percent by weight of polymer. polyester so prepared and 9 grams of bis (2-chloroethyl) 1 gram of the formalwere mixed-together andheated with stirring to 170 C. where the polymer readily dissolved yielding a clear fluid solution suitable for both wet spinning and dry spinning. Y Example VIII 2.5 grams of polyester prepared in accordancewith the procedure of Example VII were mixed with 7.5 grams ,of his (Z-chloroethyl) formal and heated with stirring to 170 C; The polymer dissolved readily and yielded a solution suitable for the preparation of a thick coating.

1 Example IX 0.5 gram of polyethylene terephthalate and 9.5 grams of his (Z-chloroethyl) formal were mixed together and heated with stirring to 170 C. toform a ole I fluid solu tion which is suitable for a thin coating.

i I Example If V .7 grams of bis (Z-chloroethyl) formal and 1 gram of chlorophenol were mixed with 2 grams of polyethylene terephthalate and heated with stirring to 170 C. where the polymer readily dissolved yielding a clear fluid solution suitable for both wet ,spinningiand dry spinning of V filaments and fibers V The polyester compositions of this invention can be usefnlly employed in the coating field, for example, in the' coating of textile fabrics. Thus, a fabric can be coated and/or impregnated with the polyester solutions described herein and then treated, that is soaked, in a non-solvent for the polyester in' order to precipitate the polyester in and on the fabric. Metals, paper and impervious films may also be coated with the polyester compositions of this I f same is-not-to be limited'to the specific embodiments thereof, except as. defined in the appended claims.

We claimza a V t 1. A new composition of matter comprising a solution of a synthetic linear condensation polyester dissolved in a solvent selected from 'the group consisting of his (2- 1 chloroethyl) formal and mixtures of his (2-chloroethyl) formal with from 3 to 50 percent, based on the total weight of the solvent, of a phenol, said polyester being selected from the group consisting of (A) polyesters formed by the reaction of at least one dicarboxylic acid selected from the group consisting of aromatic dicarboxylicacids and aliphatic dicarboxylic acids and at least one glycol of the series HO(CH OH wherein n. is an integer from 2 to 10, (B) the polyesters of (A) modified by 0.05 mol percent to 1.0 mol percent, based on the total weight of said dicarboxylic acid, of a chain terminator selected ttrom thegr'oup consisting of polyalkylvinyl 'ethers having one terminal hydroxyl group wherein the. alkyl group contains l to 4 carbon atoms, and compounds having fwherein R is selected from the group consisting of alkyl aoaaeae g a 7 groups containing 1 to 18 'carbonatomsand aryl groups containing 6, to 10 carbon atoms, m and n are integers from 2 to 22, and x isan integer from 1 to 100, indicative of the degree 'of polymerization, and (C) the polyesters of (B) containing 0.05 mol percent to 4.0 mol percent, based on the total weight of said dicarboxylic acid, of said chain terminator, modified by 0.05 mol percent to 2.4' mol percent, based on the total weight of said dicarboxylic acid, of a chain-branching agent selected from the group consisting of pentaerythritol, compounds having the formula MK I (I1) R -(O M; l i

. wherein R is an alkylene group containing from 3 to 6 carbon atoms and n is an integer from 3 to 6, compounds 3 having the formula, V

(111 7 R-'-(CH OH) V wherein R is an alkylene group containing from 2 to 6 carbon atoms, compounds havingthe formula,

CH 110K 2) 3 wherein n is an integer from 1 to 6, and compounds having the formula,

7 3. A new composition of'matter as defined inclaiml wherein the solvent is his (Z-chloroethyl) formal.

4. A new composition of matter as defined in claim 1 wherein the solvent containsbis (2- ch1oroethyl) formal and 'phenol. i p 1 5. A new composition of matter as defined in claim 1 wherein the solvent contains bis (Z-chloroethyl) formal and chlorophenol. I n I r 6. A new composition of matter as defined in claim 1 wherein the solvent contains bis (2-chloroethyl) formal and metacresol; f f t 7. A new composition of matter as defined in claim 1 whereinthe solvent containslbis (Z-chloroethyl) formal and resorcinol. a t

8. A new composition of matter-as'defined in claim 1 wherein the polyester is. polyethylene terephthalate and 12. A new composition of matter as defined'in claim 1 wherein the polyester is polyethylene .terephthalate, the chain terminator is methoxypolyethylene glycol and the chain branching agent istrimethyl trimesate.

13. A new composition of matter as defined in claim 1 wherein the polyester is polyethylene terephthalate, the chain terminator is methoxypolyethylene glycol and the chainbranching agent is pentaerythritol.

14.jAnew composition of matteras' defined in claim 1 wherein the polyester is polyethylene terephthalate, the chain terminator'ismethoxypolyethylene glycol and the chain branching agent is glycerol. V

15. A new composition of matter as defined in claim 1 wherein the polyester is polyethylene terephthalate, the

. chain terminator is ethoxypolyethylene glycol and the chain branching agent is sorbitol.

16. A new composition of matter comprising a solution of a synthetic linear condensation polyester dissolved in a solvent selected from the group consisting of his (2- chloroethyl) formal and mixtures of his (2-chloroethyl) formal with from 3 to 50 percent, based on the total weight of the solvent, of a phenol, said polyester being selected from the group consisting of (A) polyesters formed by the reaction of at least one dicarboxylic acid selected from the group consisting of aromatic dicarboxylic acids and aliphatic dicarboxylic acids and at least one glycol of the series HO(CH ),,OH whereinrn is an integar from 2 to 10, (B) the polyesters of (A) modified by 0.05 mol percent to 1.0 mol percent, based on the total weight of said dicarboxylic acid, of a chain terminator selected from the group consisting of polyalkylvinyl ethers having one terminal hydroxyl group wherein the alkyl group contains 1 to 4 carbon atoms, and compounds having the formula,

wherein R is selected from the group consisting of alkyl groups containing 1 to 18 carbon atoms and aryl groups containing 6 to 10 carbon atoms, m and n are integers from 2 to 22, and x is an integer from 1 to 100, indicative of the degree of polymerization, and (C) the polyesters of (B) containing 0.05 mol percent to 4.0 mol percent, based on the total weight of said dicarboxylic acid, of said chain terminator, modified by 0.05 mol percent to 2.4 mol percent based on the total weight of said dicarboxylic acid, of a chain-branching agent selected from the group consisting of pentaerythritol, compounds having the formula,

wherein R is an alkylene group containing from 3 to 6 carbon atoms and n is an integer from 3 to 6, and compounds having the formula,

(HI) R(CH OH) 3 wherein R is an alkylene group containing from 2 to 6 carbon atoms, compounds having the formula,

F (oHnoH L 2 1 wherein n is an integer from 1 to 6, and compounds having the formula,

wherein n is an integer from 3 to 4 and R is an alkyl group containing 1 to 3 carbon atoms, said solvent being employed in a range of 75 to 90 percent, based on the total weight of the composition.

17. A new fiber-forming composition of matter comprising a miscible mixture of 10 to percent, based on the total weight of the composition, of polyethylene terephthalate having a molecular weight of at least 10,000 and a solvent selected from the group consisting of his (2- chloroethyl) formal and mixtures of bis (2-chloroethy1) formal with from 3 to 50 percent, based on the total weight of the solvent, of a phenol.

18. A process for preparing a new composition of mat ter comprising mixing a synthetic linear condensationpolyester with a solvent selected from the group consisting of his (Z-chloroethyl) formal and mixtures of his (Z-chloroethyl) formal with from 3 to 50 percent, based on the total weight of the solvent, of a phenol, and heating the mixture to a temperature in a range of C. to the boiling point of the mixture, said polyester being selected from the group consisting of (A) polyesters formed by the reaction of at least one dicarboxylic acid selected from the group consisting of aromatic dicarboxylic acids and aliphatic dicarboxylic acids and at least one glycol of the series HO(CH ),,OH wherein n is an integer from 2 to 10, (B) the polyesters of (A) modified by 0.05 mol percent to 1.0 mol percent, based on the total Weight of said dicarboxylic acid, of a chain terminator selected from the group consisting of polyalkylvinyl ethers having one terminal hydroxyl group Whereinthe alkyl group contains 1 to 4 carbon atoms, and compounds having the formula,

wherein R is selected from the group consisting of alkyl groups containing 1 to 18 carbon, atoms and aryl groups containing 6 to 10 carbon atoms, m and n are integers from'Z to 22, and x is an integer from 1 to 100, indicative of the degree of polymerization, and (C) the polyesters of (B) containing 0.05 mol percent to 4.0 mol percent, based on the total weight of said dicarboxylic acid, of said chain terminator, modified by 0.05 mol percent to 2.4 mol percent based on the total weight of said dicarboxylic acid, of a chain-branching agent selected from the group consisting of pentaerythritol, compounds having the formula,

wherein R is an alkylene group containing from 3 to 6 carbon atoms and n is an integer from 3 to 6, compounds having the formula,

(III) R--(CH OH) 3 wherein R is an alkylene group containing from 2 to 6 carbon atoms, compounds having the formula wherein n is an integer from 1 to 6, and compounds having the formula,

wherein n is an integer from 3 to 4 and R is an alkyl group containing 1 to 3 carbon atoms.

19. The process as defined in claim 18 wherein the solvent is bis (2-chloroethyl) formal.

20. The process as defined in claim 18 wherein the sol vent contains bis (Z-chloroethyl) formal and phenol.

References Cited in the file of this patent UNITED STATES PATENTS 2,895,946 Hufiiman July 21, 1959 

1. A NEW COMPOSITION OF MATTER COMPRISING A SOLUTION OF A SYNTHETIC LINEAR CONDENSATION POLYESTER DISSOLVED IN A SOLVENT SELECTED FROM THE GROUP CONSISTING OF BIS(2CHLOROETHYL) FORMAL AND MIXTURES OF BIS (2-CHLOROETHYL FORMAL WITH FROM 3 TO 50 PERCENT BASED ON THE TOTAL WEIGHT OF THE SOLVENT, OF A PHENOL, SAID POLYESTER BEING SELECTED FROM THE GROUP CONSISTING OF (A) POLYESTERS FORMED BY THE REACTION OF AT LEAST ONE DICARBOXYLIC ACID SELECTED FROM THE GROUP CONSISTING OF AROMATIC DICARBOXYLIC ACIDS AND ALIPHATIC DICARBOXYLIC ACIDS AND AT LEAST ONE GLYCOL OF THE SERIES HO(CH2)NOH WHERIN N IS AN INTEGER FROM 2 TO 10, (B) THE POLYESTERS OF (A) MODIFIED BY 0.05 MOL PERCENT TO 1.0 MOL PERCENT, BASED ON THE TOTAL WEIGHT OF SAID DICARBOXYLIC ACID, OF A CHAIN TERMINATOR SELECTED FROM THE GROUP CONSISTING OF POLYALKYLVINYL ETHERS HAVING ONE TERMINAL HYDROXYL GROUP WHERIN THE ALKYL GROUP CONTAINS 1 TO 4 CARBON ATOMS, AND COMPOUNDS HAVING THE FORMULA, 